It is our purpose to establish a Clinical Research Center for the systematic study of the pathogenesis of acute and recurrent otitis media. We will also study the pathogenesis of chronic otitis media with special reference to such common sequelae of this disorder as sensorineural hearing loss and the middle ear cleft abnormalities of tympanosclerosis and granulation tissue. An attempt will be made to develop a biologically meaningful classification including possible aspects of genetic factors of these disorders not only to more accurately assess the specific pathogenetic mechanisms but also to provide a basis of uniformity for more rational diagnosis and for scientific and clinical communication. Otopathological studies of human and animal otitis media will be conducted throughout. Three major approaches to the study of pathogenetic mechanisms will be used: 1) the role of mechanical eustachian tube dysfunction; 2) the role of local and systemic immunological mechanisms; and 3) the role of bacterial infection and of bacterial fractions and products. Parallel studies in humans and animals will be undertaken to provide a cross-questioning and cross fertilizing approach to the study of pathogenesis: an interdisciplinary approach will be employed in all these efforts and will include established investigators in the fields of otolaryngology, audiology, pediatrics, genetics, biometry, pathology, biochemistry, histochemistry, otophysiology, immunology, microbiology and infectious diseases.